My car is 11 months old, and I've just replaced the lithium battery in the key fob for a 2nd time. The battery wasn't outright dead, but must have been quite weak because the range for key fob remote operation was very short, and unlocking action was inconsistent. New battery, and everything works fine.

How often are other C6 owners replacing their fob batteries?

Not sure if I really needed to, but I was having problems starting the car w/ keyless start button. Sometimes it would take several pushes before the engine would turn.

So far it's been working w/o problem since changing.

when I pressed the key button it did not spring out.

my '01 4.2 still has the original battery! I'm sure it will not last forever.